From: "Rafael J. Wysocki" Subject: Re: [PATCH] ACPI / Video: Fix initial brightness problem on Acer Ferrari One Date: Wed, 7 Apr 2010 21:13:45 +0200 Message-ID: <201004072113.45400.rjw@sisk.pl> References: <201004010319.19366.rjw@sisk.pl> <201004062051.16998.rjw@sisk.pl> <1270619239.24064.4965.camel@rzhang1-desktop> Mime-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: Received: from ogre.sisk.pl ([217.79.144.158]:37361 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756955Ab0DGTKu (ORCPT ); Wed, 7 Apr 2010 15:10:50 -0400 In-Reply-To: <1270619239.24064.4965.camel@rzhang1-desktop> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Zhang Rui Cc: Len Brown , ACPI Devel Maling List , Matthew Garrett , "Moore, Robert" On Wednesday 07 April 2010, Zhang Rui wrote: > On Wed, 2010-04-07 at 02:51 +0800, Rafael J. Wysocki wrote: > > On Tuesday 06 April 2010, Zhang Rui wrote: > > > On Mon, 2010-04-05 at 07:19 +0800, Rafael J. Wysocki wrote: > > > > On Friday 02 April 2010, Rafael J. Wysocki wrote: > > > > > On Friday 02 April 2010, Zhang Rui wrote: > > > > > > On Fri, 2010-04-02 at 03:45 +0800, Rafael J. Wysocki wrote: > > > > > > > On Thursday 01 April 2010, Zhang Rui wrote: > > > > > > > > On Thu, 2010-04-01 at 09:34 +0800, Zhang Rui wrote: > > > > > > > > > On Thu, 2010-04-01 at 09:19 +0800, Rafael J. Wysocki wrote: > > > > > > > > This patch may not be necessary after all. > > > > > > > > I'll repost it if I find it's still needed. > > > > > > > okay. > > > I re-read the code and find out that you're right. sorry for the noise. > > > > > > please feel free to add an Acked-by from me next time you send it to the > > > list. > > > > Thanks, but it looks like only one box is affected and because its BIOS returns > > the minimal brightness value in the initial _BQC. > > > I'm not sure if it's worth > > changing the current behavior because of that. > > > > well. in the ACPI video driver, we assume that BIOS sets a PROPER > brightness level when loading OS. > so we use the _BQC return value as the default backlight, but apparently > this doesn't work well in this BIOS. > I would rather say this is a BIOS problem, which I'm not sure if we > should fix it in Linux kernel or not... Yes, exactly. If more systems were affected, I'd say it would be worth considering, but not if there's only one. Thanks, Rafael